Resumen

LARRINAGA CORTINA, Eduardo F; ALONSO FERNANDEZ, vid N; ALFONSO LAGUARDIA, Rodolfo  y  ALONSO SAMPER, José L. Patient-specific intensity modulated radiotherapy quality assurance using an electronic portal imaging device. Nucleus [online]. 2016, n.59, pp. 19-24. ISSN 2075-5635.

A modern clinical electron linear accelerator was commissioned at the Department of Radiotherapy in the Oncology and Radiobiology Institute. The use of electronic portal image device (EPID) for patient-specific intensity modulated radiotherapy (IMRT) quality assurance is assessed and validated. An IMRT step & shoot approach, using multileaf collimator was used. The EPID dose-response curve was determined for a 6MV photon beam. The EPID effective water scattering depth (Descripción: D:\Scielo\Nucleus html\n 59\img\e01055916.jpg) was assessed through measurements of its response versus field size variation and compared with the output factor scatter at different depths, calculated with a radiotherapy treatment planning system (TPS). Dose profiles and dose maps were calculated at Descripción: D:\Scielo\Nucleus html\n 59\img\e01055916.jpg with the TPS, using a collapsed beam setup. The dose maps and profiles were compared with the processed EPID images for simple cases (i.e. open and wedged fields) and a more complex case (a head and neck IMRT clinical case). Comparison was performed using the Gamma function. Results showed Gamma passing rates higher than 90 % for all compared points, using comparison criteria of dose difference 3% and 4mm of distance to agreement

Palabras clave : gamma function; radiotherapy; quality assurance; linear accelerators; image processing.

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